1. Field of the Invention
The present invention relates to an imaging apparatus, such as a digital camera, which can transfer an image with a wireless communication unit.
2. Description of the Related Art
More specifically, the present invention relates to a camera system that includes a camera body part controlling actual shooting processing, and a monitor display part separable from the camera body part that controls the display of a captured image.
An image captured by a digital camera can be directly transmitted to other devices via a wireless local area network (LAN) or other wireless communication medium.
FIG. 16 illustrates an internal system arrangement of a conventional camera 101. The camera 101 includes a battery 114 and a power control circuit 115 that controls power supply to various units in the camera.
When a user pushes a release button on the camera 101, a camera control unit 102 detects a change of a camera switch (SW) 103 and starts a camera shooting control.
An image sensor 104 captures an image of an object and sends a captured image to a processor 105. The processor 105 temporarily stores the captured image into a buffer memory 107. The processor 105 can successively read images from the buffer memory 107 and apply predetermined image processing (e.g., matrix processing, γ conversion, and JPEG conversion) to each read image. The processor 105 can write a processed image to a nonvolatile memory 106 in the camera or send the processed image to a memory card 109 via an external card interface (I/F) 108.
A monitor unit (e.g., a TFT liquid crystal screen) 113, provided on a back surface of the camera, enables a user to confirm a captured image. When a user operates a monitor SW 112 on the side of the monitor unit 113, the monitor unit 113 displays various screens so that the user can view an intended image on the screen or can set various parameters of the camera (including the size/mode of a shooting image and developing parameters) on a menu screen.
The image data having been subjected to the image processing can be transferred via a wireless communication unit 110 (e.g., a wireless LAN) to an external network or to a personal computer (PC). In this case, the processor 105 reads an image from the nonvolatile memory 106 of the camera or from the memory card 109. Then, the processor 105 applies various communication protocol processing (i.e., processing required for transferring image data to a network system) to the read image and transfers the processed image to an external PC 116 via the wireless communication unit 110 and an antenna 111.
The wireless communication unit 110 includes a media access control (MAC) unit that can control a communication procedure in a media access control layer (MAC layer) at a network protocol level and a physical layer (PHY) unit that can actually modulate and convert the data into a signal having a predetermined frequency band. For example, according to the standard of a general wireless LAN, the converted signal is a 2.4 GHz band signal for 802.11b/g or a 5 GHz band signal for 802.11a.
There is a conventional camera including a camera body unit and a monitor unit that are separable from each other and can transmit/receive a captured image or a playback image via a wireless communication medium.
For example, as discussed in Japanese Patent Application Laid-Open No. 8-205016, a video camera body can transmit a captured image via a wireless communication medium to a remote monitor unit and the remote monitor unit can display a received image. If a user operates the monitor unit, the monitor unit performs a remote control for operating the video camera body via the wireless communication.
Furthermore, as discussed in Japanese Patent Application Laid-Open No. 9-261519, an imaging unit of a video camera is separable from a recording unit including a monitor unit that displays a captured image. The imaging unit can transmit a captured image to the recording unit via a wireless communication medium. The recording unit includes a predetermined storage medium (e.g., a magnetic tape) that stores the images transmitted from the imaging unit.
Furthermore, as discussed in Japanese Patent Application Laid-Open No. 2004-088396, a digital camera includes an imaging unit separable from a camera body unit including a monitor unit that displays a captured image. When a user performs a release operation on the camera body unit, the imaging unit can start a shooting control.
More specifically, the camera body unit detects a user's pressing operation on a release button and transmits a detection signal to the imaging unit via a wireless communication medium. In response to the detection signal, the imaging unit performs a shooting control and transmits captured image data to the camera body unit via the wireless communication medium. The camera body unit stores the received image data into a memory card attached to the camera body.
Furthermore, as discussed in Japanese Patent Application Laid-Open No. 2004-187127, a camera can include an imaging unit separable from a camera body unit that applies image processing to image data captured by the imaging unit. The imaging unit includes a built-in memory for temporarily storing image data. The camera body unit has a memory card.
According to the camera having the above-described arrangement, the imaging unit temporarily stores the captured image data into the built-in memory if a user separates the imaging unit from the camera body unit.
As discussed in the above-described prior art, even when a camera includes a body unit and a monitor unit which are separable from each other, the body unit and the monitor unit can perform operations independently if the camera includes a processor in the body unit and another processor in the monitor unit.
On the other hand, the camera can flexibly use two processors in a condition where a user unites (or integrates) the body unit with the monitor unit. Thus, it is desirable to effectively use two processors for processing the image data.